Stair construction



July 2,1, 1931. H. CHAMBERS STAIR CONSTRUCTION 6. 1928 5 Sheets-Sheet l Filed Dec.

July 21, 1931. H. CHAMBERS 1,815,048

SfIAIR CONSTRUCTION Filed neg. e. 1928 l 5 sheets-'sheet 2 A T RNEYS.

July`21, 1931. l

' H. 'CHAMBERS l sTAIR CONSTRUCTION 6, 1928 5 sheets-sheet 5 Filed Dec.

JN VENTO/e.

//a/wby/a/f (ia/fibers 1 BY L ORNE YS.

July 21, i931. H, CHAMBERS 1,815,048

STAIR CONSTRUCTION Filed Dec. 6, 1928 5 Sheets-Sheet 4 wm@ Z5,

/ A NEYS.

l Juli' 2.1, 19.31. I H, CHAMBERS t` 1,815,048 I sTAIR CONSTRUCTION Filed Dec-.f e, '1928 5 sheets-sheet 5 A? RNEYS.

Patented July 21, 1931 HARRINGT'ON CHAMBERS, OF FLUSHING, LONG ISLAND, NEWVYORK STAIR CONSTRUCTION Application filed December 6, 1928. Serial No. 324,095.

This invention relates to stair construction and is directed more particularly to improvements in constructions for use in small dwellings. l

It has heretofore been proposed to provide so-called' disappearing stairways in small dwelling houses, such as bungalows or two story and attic dwellings. These stairways have been so constructed that 1o they are normally elevated into the attic so as to leave the lower floor wholly unencumbered by their presence and they are adapted to be drawn down to the lower Vfloor when it is desired to provide for passage between the floors. Such constructions have universally been built to'be operated by cables wound around spring actuated drums which, when the stair is pulled down, serve to place the springs under tension for kthe purpose of counterbalancing the stair. Experience has proven, however, that these stairs, because of their cable suspension require a considerable amount of manual effort to operate and have rnot proven wholly satisfactory for this and other reasons well known to the trade.

lVith the foregoing considerations in mind, the object of the present invention is to provide a thoroughly simple and efficient construction which may be operated` without anyl appreciable manual effort and which willbe more strong and durable than prior constructions.

An important feature of theV present invention consists in novel means for counterbalancing the stair, more particularly characterized by the fact that relatively long helical springs are utilized to act directly upon the stair construction instead of strong coil springs as heretofore used acting through cables.

My novel arrangement contemplates springs for counterbalancing the weight of the stair in a vertical direction, and separate springs for counterbalancing the stairs for sliding movement in the direction of their length and these springs are so proportioned as to their elasticity as to bring about a smooth cushioned operation with a minimum of manual effort.

A further feature of the invention consists in the employment of eiiicient means for locking the stair in its down position, so that it cannot inadvertently shift, but

will provide at all times, when in such posir tion, ay safe passage between floors.

A feature of marked practical importance inherent in the present invention is the manner in which thestair is supported for pivotal movementk and also partially for sliding movement. 1t has heretofore been common to mount the stair entirely on a trap door which in turn is hinged to the ceiling of the jamb of the stair well Opening. Thus the weight of the entire structure isimposed on the hinges of the door. This results in a structurally weak arrangement.

According to the present invention, in contradistinction, a greater portion of the weight of the stair is carried by a shaft firmly anchored in the well opening and serving not only to carry the weight of the stair, but also providing a mounting for sheaves with which the counterbalancing springs cooperate. By the latter method a more secure mounting is obtained and installation of the stair may be more efficiently and expeditiously accomplished.

The stair of the present'invention is, in its preferredr form, provided at its upper end witha so-called top step or trip secured to the stringers of the stair by means of suitable metal brackets which also serve as a limiting means for the downward movement of the stair and as a mounting for the safety latch.

The foregoing features and others, hereinafter more fully described, result in a stair construction relatively simple to install, while highly efficient in the performance of its intended functions.

Features of the invention, other than those adverted to, will be apparent from the hereinafter detailed description and claims, when read in conjunction with the accompanying drawings. n

The accompanying drawings illustrate one practical embodiment of the invention, but the construction therein shown is to be understood as illustrative, only, and not as defining the limits of the invention.

Figure 1 is a vertical section through stair construction embodying the present invention, the stair being shown in its down position.

Figure 2 is also a vertical section, partly broken away, showing the'stair in van'intermediate position.

Figure 3 shows the stair in an up or compacted position.

Figures 4 and 5 are detail sections showing parts of the stair removed andillustrating more particularlythemanner in which the stair and door are counterbalanced.

Figure G is a section on the lineG-G of Figure 3.

Figure 7 is a section on the line 7-I7 of Figure 3.

Figure 8 is a somewhat enlarged vertical section taken in approximately the plane of the line 88 of Figure 6 with-part of the stairfbroken away and showing the mechanism for mounting the stair on the trap door and in the well opening in elevation.

Figure 9 is a detail view showing the manner of anchoring the ends of the springs on the stair and j amb.

Figure-10 is a verticalv section through the upper end ofthe stair.

For the-purpose of concrete description, let it be assumed that 1 designates the floor level of a lower floor and that 2 designates the floor level of an upper floor. 8 designates'the ceiling of the upper floor 2 and .4 the well opening in the upper tloor2. This well opening is provided with a suitable jamb 3 and with which jamb is associated .a suitable. Enis'hin'g strip 5. Tliewell opening 4 is provided with'a trap door 6 hinged at 7 to the jamb Sand adapted to swing on these hinges from a positionA wherein the trap door will close the well opening as shown in Fig. 8 into the downwardly inclined position Vshown in 'Figure 1 and vice versa. This trap door is made of strong, rigid construetion and is preferably longitudinally and transversely strengthened by suitable stitl'eningbraces designated 8.

Extending transversely across that end of the well opening at which the door is hinged is a shaft 9. This shaft is firmly secured in place by means of brackets 10` as shown in Figure G, so as to be rigidly mounted in position and to extend for thefull width of the opening. On thisrshaft are mounted four sheaves which aredesignated 11, 11 and 12, 12. VAll of 4thesevsheavesare intended for cooperationv with long coil springs, the purpose of which is tov counterbalance the stair and door. Y Y

Two springs are employed for each of these purposes, those designated 14 serving to counterbalance the pivotal movement of the door and ystairwhile the springs 15 funcspring 14 extends 'downwardly land is anchored to the free end of the trap door as shown at 119 in Figs. 1, 3 and 7. The spring is always under `sufficient tension to lift the door into the closedposition shown in Fig. 4 and to maintain it seated against a door stop 20 associated with the jamb 3. Figure 9 `shows the anchorage construction for the spring ends. A shackle or link 18a serves to 'secure each spring to its brackety 18 or 19 for slight pivotable movement so that there will be a straight pull on the shackles `at all times, irrespective of the angle at which it is exerted.

The stair embodies parallel stringers 21 ofsuitable length and between the stringere extend the treads 22. The stair may be provided with risers if desired although as shown in the drawings the risers are ornitted. stringers and support a hand rail 24. One of these hand rails may be positioned at each side of the stair if desired. The stair is mounted for movement in the direction of its vlength upon rollers associated with the trap door and with the shaft 9. These rollers are best shown in lFigures G, 7 and 8. Rollers 25are mounted on the shaft 9, so as to underlie the lower edges of thestringers and to provide for rolling coaction between these rollers and stringers. Similar rollers 2S are mounted on brackets 27 fixed to the free end of the door 6 and are also adapted to underlie Aand support the stringers of the stair.

Each Stringer is provided in its outer face with a longitudinally extending `guide channel 28, and on the brackets 27 are mounted guide pins 29 which extend into these channels. Guide brackets 30 vare also mounted on the 4shaft 9 and each Aof these brackets carries a guide bar 31 vwhich also its into one of the channels 28. The guide pins 29 and the guide bars 31 engage the walls of the guide channels 28 in both of the stringers and hold these stringers in engagement with the rollers 2G and25, respectively, while these rollers support the weight of the stair and at the same time permit movement of the stair in the direction of its length. Flanges 27a and 30a preclude lateral shi-fting-of the stair with respect to the rollers so thatv the under edges of the stringere will cooperate with Vsaid rollers at all times. Suitable stops 32 limit the upward move- Hand rail posts 28 are secured to the .y of the stringers 21 of the stair.

ment 0f the stair through engagement with the brackets 27 as clearly shown in Fig. 8.

The stair is counterbalanced for move-V ment in the direction of its length by the springs 15 hereinbefore referred to and the arrangement of which springs is clearly shown in Fig. 5. In this figure, one end of each of the springs 15 is secured to one of the brackets 18 which carries the sheaves 17 by the shackles or links as shown. Each of these springs 15 extend to and about one of the sheaves 12 mounted. on the shaft 9 and from thence extend to and are secured to brackets 32 mounted on the outer sides These springs 15 are always under tension and their purpose is to impart a sufficient upward pull upon the stair as to substantially counterbalance the weight of the stair when in down position. In other words, these springs are sufficiently strong, so that the stair may be moved vertically by manual manipulation without requiring the expenditure of appreciable manual force in this connection.

Similarly the springs 14 are sufficiently strong to carry the greater portion of the Weight imposed on the trap door 6, so that the door may be opened or closed by the application of relatively little manual effort. It will be noted, however, that the spring 15 is somewhat shorter than the spring 14. Consequently it will be 0f correspondingly greater tension. The relation of the lengths of the springs is such that operations of the respective parts will be properly adjusted to one another.

Under normal conditions when it is desired that the stair be in an up position and out of the way, the parts are as illustrated in Fig. 3. It will be noted from this view that the trap door 6 is closed and that the stair is in substantially horizontal position in for example the attic. l

In order to have access to the stair from the lower floor a pull cord or chain 33 is associated with the trap door. Nhen a downward pull is manually exerted upon this chain, the door is swung downwardly on its hinges 7 into substantially the position shown inr Fig. 2. Then the door is thus tilted downwardly, the stair will slide down to within approximately one foot of the lower floor due to gravity or inertia. The balance of the downward movement requires slight manual effort. As the stair reaches its completely lowered position indicated in dotted lines in Figure 2, it is adapted to be locked in this position by suitable latches neXt to be described.

In order to provide proper landing between the upper end of the stair and the upper floor, the eXtreme upper end of the stair is preferably provided with a top step 22a supported ron the stringers by metal plates 36 in such manner that when the stair is in downposition the top of the ste 22a will be fiush with the upper floor leve rlhese plates are shown best in Fig. 10. They are preferably made as shown so that they can be used as either rights or lefts. Each plate is secured to one of the stringers by screws 37 and to the top step 22a by screws 38. The recesses 39 areV so positioned that when the stair is let down, stop pins 35 will enter into the recesses and positively stop the stair against further, downward movement. Pivoted adjacent one of the recesses 39 is a latch 34, its pivot 40 being carried by the plate 36 and positioned above and on about the line of the lower edges '0f the stringers. The latch is a gravity latch and it is provided with a recess 39a. The lower edge of the latch is also formed with a cam surface 41 leading to this recess.

When the stair is moved downwardly, the pin 35 engages with the cam surface 41 and causes the latch to be lifted to permit the pin to enter both the recesses 39 and 39a 'nk in the plate and latch. As soon as this occurs the latch drops by gravity and locks the pin in place.- An adjustable stop screw 42 is carried by ythe latch to control the -locking position of the latch with respect to the pin so that the latch can be tripped to disengage the pin 35 by imparting to the stair a sudden upward thrust. This will swing the latch up and release the Vpin to permit elevation of the stair. The locking and unlocking positions of the latch are clearly shown inFig. 10. The plates 36 are stamped or offset slightly as indicated at 43 so as to clear the stair guides 30a.

It will be apparent from the foregoing detailed description that the stair constrution of this invention may be economically built and that it may be installed not only during the initial construction of houses,

but it mayalso be installed in old houses without.appreciable change in the building construction. The arrangement is easily operated without appreciable manual effort.

Vf hen the stair is in down position, it

provides a rigid, safe and convenient means 1 of access to therupper fioor and does not embody the hazard incident to the employment of ladders and the like. The stair of the present invention is as safe to ascend and descend, when locked in down position,

The structure has been "described and illustrated as made of wood although -fit may be madefof metal withoutdeparting from this invention, the scope Aof whichisto be understood Ias fully Icommensurate with .Y the appended claims.

Having Vthus .fully described Vthe invention, .what I claim as new and .desirelto secureby Letters Patent is:

1. In-a stair constructionadaptedto be used between lowerand npper floors, the latter of which is provided with astairwwell opening, a-trap "door adapted when. in horizontal position to close 4the opening vand which door is hinged tobe opened into a downwardly inclined position, guide rollers mounted nearthe freefend of the door, a shaft-extending acrossuthe well opening at the end thereof ,atwhichthe door'is hinged and which shaft is supported at;its opposite enldsionthe janib ofsaid Well opening, rollers carried by said shaft, a rigid stair embodying stringers and'treads mounted with the lower 4edges of vthe stringers bearing uponthe rollers on the door l:and shaft to mount .said .stair foi-.longitudinal movement, said stringers being-provided with longitudinal guides, guide .members associated with the rollers and engaging with the guidesto hold the stringersin engagement with the rollers, helical coil springs for' counterbalancing .the weight of .the stair in the direction of its length and the weight of the door landstair in a .substantially .vertical direction, and locking means .to lock thelstair-in itsvlowered position vagainst inadvertent lifting movement,

2. In a stair construction adapted to be used between lower and upper floors, the latter of whichis provided ywith a stair' well opening, a trap door `.adapted when in horizontal position to close the .opening and which door is -hinged to be opened intoa downwardly inclined position, guide rollers mounted near the free end `of the door, a shaft extending .across the well opening at the end thereof at which the door is hinged and which shaft is supported .at its opposite ends on the jambofsaidwell opening, rollers carried by said shaft, a rigid .stair embodying stringers and treads mounted with the loweredges of .the stringers` bearing upon the rollers on the door and shaft to mount said stair for longitudinal movement, said stringers being provided with longitudinal guides, guide members associatedwith the rollers and engaging with the guides to hold the stringers inl engagement with the rollers, helical coil springs for counterbalancing the weight ofthe stair in the direction of its length and the weight of the door and stair in .a substantially vertical direction, said stair :being provided at its upper end with attaching plates vsecured .to the stringers-anldvprovided w-itlrrecesses, atop step secured to theiattaching plates, .a detent also provided with alrecesspivotally mounted on one of said attaching plates, a piirmount'ed on one of said guides and which pin is adapted to vactuate the latch to enter the 'recesses of the latch and attaching plate to lockthe stairin its down position, and an adjustingmember :for adjusting the latch forproper engagement with the pin.

3. In a stair construction adapted to be used between lower `and upper floors, the latter of which is provided with a stair well .opening having a hinged trap doortherein, a rigid stair mounted for sliding movement longitudinally-of the door and embodying stringers Sand treads,helical `coil springs interposed betweenthe stair and a relatively fixed anchorage at the upper Hoor to counterbalance the weight of the stair in the direction of its length, and additional helical -coil springs. interposed between the door and a relatively fixed anchorage at the upper floor to counterbalancc the weight of the stair and door in a substantially vertical direction, said latter sp ings being wholly separate and independent in operation of the vsaid springs to counterbalance the weight of the stair in the direction of its length.

v4.*In a stair construction adapted to be nsed between lower and upper i'ioors, the latter of which is .provided with a stair well opening having a hingedtrap door therein, .a rigid stair mounted for sliding movement longitudinally of the door and embodying stringersand treads, helical coil. springs interposed between the stair and a relatively fixed anchorage at the upper floor to counterbalance-the weight of the stair inthe direction of its length, and additional helical coil springs interposed between the door andl a relatively fixed anchorage at the upper floor to counterbalance the weight of the stair and door in a substantially vertical direction, said latter springs being wholly separate and independent in operl tion ofthe said springs to counterbalance the weight of the stair in the direction of its length, and means for locking the stair in `.its lowered position against inadvertent lifting movement.

5. .In a stair construction adapted to be used between lower and upper floors, the latter of `which is provided with a stair well opening having a` hinged trap door therein, guide rollers mounted near the free end of the door, a shaft extending uninterruptedly across the well opening at the end thereof at which the door is hinged and which shaft is supported at its opposite ends on the j amb on opposite sides of said well opening` rollers carried by said shaft, a rigid stair embodying stringers and treads mounted with the lower edges of the stringers bearing upon the rollers on the :door and shaft tomount said stair for longitudinal movement, helical coil springs secured to the stair and jamb for counterbalancing the weight of the stair in the direction of its length, and helical coil springs, separate from and independent of the said coil springs of the stair and jamb, secured to the jamb and door for counterbalancing the weight of the door and stair in a substantially vertical direction, whereby the stair is counterbalanced in the direction of its length independently of its counterbalancing in a substantially vertical direction.

6. In a stair construction adapted to be used between lower and upper floors, the latter of which is provided with a stair well opening having a hinged trap door therein, guide rollers mounted near the free end of the door, aA shaft extending uninterruptedly across the well opening at the end thereof at which the door is hingedand which shaft is supported at its opposite ends on the opposite sides of the jamb of said well opening, rollers carried by said shaft, sheaves also mounted on said shaft, a rigid stair embodying stringers and treads mounted with the lower edges ofthe stringers bearing upon the rollers on the door and shaft, to mount said stair for longitudinal movement, coil springs, one end of each of which is secured to the stair and which coil springs extend around the sheaves and are suitably anchored with respect to the well jamb to counterbalance the weight of the stair in the direction of its length, and additional coil springs, one end of each of which is secured to the jamb, and which latter springs extend around the sheaves and are secured at their other ends to the door adjacent its free end, to counterbalance the weight of the stair and door in a substantially vertical direction, and additional directional sheaves coacting with the last mentioned springs between the sheaves on the shaft and the free end of the door and which directional sheaves are supported on the well j amb, whereby the weight of the stair in the direction of its length is counterbalanced independentlyy of the weight of the stair and door`in a substantially vertical direction.

7 In a stair construction adapted to be used between lower and upper floors, the latter of which is provided with a stair well opening having a hinged trap door therein, a rigid stair mounted for sliding movement longitudinally of the .door and embodying stringers and treads, helical coil springs interposed between the stair and a relatively fixed anchorage at the upper iloor to counterbalance the weight of the stair in the direction of its length, and additional helical coil springs interposed between the door and a relatively fixed anchorage at the upper floor to counterbalance the weight of the stair and door in a substantially vertical HARRINGTON CHAMBERS. 

